It seems you still didn't have server and client coded split correctly.

I don't ask you for more but just you set up a dedicated server (it's not even that hard nor time consuming) and test if it even starts without issues before release next update. If you only dev client-only mods - please mark them as such. There is no reason for out-source some stuff as a "lib" when it does client-specific GUI stuff it obviously shouldn't and can't therefore run on dedicated server. That's even worse than that magic reflection vodoo you do in the initializer - but I guess that's something Forge/ASM related and shouldn't be done in real-world code not constraint by an overall crap API.